s/uri/iri since we accept IRIs

fix build

fix remote_user for CGI and add -6 flag to enable ipv6

accept both ipv4 and ipv6

log also the port of the client

make FATAL and LOG inline functions other functions that aren't macros anymore. LOG went under a rename to logs because log is a builtin (the math function), or so gcc says.

macro reordering and while there replace SAFE_SETENV with an inline function. LOG is more difficult to transform into an inline function, given the string concatenations it does. The other LOG* and FATAL macros are fine as they already are.

simplify loop todo was initially there for an optimization: don't loop to MAX_USERS when you know the upper limit is todo.

simplify unveil/pledge calls

rename cgi_setpoll_on_* to cgi_poll_on_*

initialize error string to avoid returning garbage

ignore also SIGHUP SIGHUP is sent when the tty is detached and by default kills the process. When we run in the background we don't care anymore about the tty, so it should be safe for us to ignore SIGHUP. (frankly, I expected daemon(3) to do stuff like this for us).

fix CGI with new IRI parser With new IRI, parser the old assumption of path starting with ./ is no longer valid.

implement a valid RFC3986 (URI) parser Up until now I used a "poor man" approach: the uri parser is barely a parser, it tries to extract the path from the request, with some minor checking, and that's all. This obviously is not RFC3986-compliant. The new RFC3986 (URI) parser should be fully compliant. It may accept some invalid URI, but shouldn't reject or mis-parse valid URI. (in particular, the rule for the path is way more relaxed in this parser than it is in the RFC text). A difference with RFC3986 is that we don't even try to parse the (optional) userinfo part of a URI: following the Gemini spec we treat it as an error. A further caveats is that %2F in the path part of the URI is indistinguishable from a literal '/': this is NOT conforming, but due to the scope and use of gmid, I don't see how treat a %2F sequence in the path (reject the URI?).

moving declarations to header file